Pituitary Hypofunction

Question 1

Is it common for pituitary hypo function to affect specific hormones?

Answer 1

No

Question 2

What is panhypopituitarism?

Answer 2

All the pituitary hormones are under secreted

Question 3

What 5 things does panhypopituitarism result in?

Answer 3

• Hypothyroidism
• Hypoadrenalism
• Growth failure
• Hypogonadism
• Diabetes Insipidus

Question 4

Name some causes of panhypopituitarism?

Answer 4

Tumours or metastases
Infections
Iatrogenic
Granulomatous disease
Vascular disease
Trauma
Autoimmune

Question 5

What is Sheehan’s Syndrome?

Answer 5

This occurs during pregnancy when the pituitary gland enlarges and causes ischaemia of the gland

Question 6

What are some signs and symptoms of hypogonadism?

Answer 6

Menstrual irregularities
Infertility
Impotence
Gynaecomastia

Question 7

What are some general features of panhypopituitarism?

Answer 7

Abdominal obesity
Loss of facial, axillary and pubic hair
Dry skin and hair

Question 8

What therapy is always given first in panhypopituitarism?

Answer 8

Hydrocortisone 10-25mg/day

Question 9

Apart from hydrocortisone, what other hormone replacement therapies should be given in panhypopituitarism?

Answer 9

• Thyroxine 100-150mcg/day
• ADH desmospray nasal or tablets
• Nightly SC GH
• Sex hormone replacement

Question 10

What is the sex hormone replacement therapy in females?

Answer 10

HRT/progesterone/oestrogen pill

Question 11

What is the sex hormone replacement therapy in males?

Answer 11

Testosterone

Question 12

What is the relationship between testosterone therapy and prostate cancer?

Answer 12

Testosterone therapy does not cause prostate cancer however it can enlarge the prostate and cause growth of a cancer if it is already there

Question 13

What should always be done before starting testosterone therapy?

Answer 13

Screen for prostate cancer

Question 14

What are two other side effects of testosterone therapy and how are they monitored?

Answer 14

Polycythaemia- monitor FBC

Hepatitis- monitor FBC

Question 15

What is the only type of testosterone therapy that can causes hepatitis?

Answer 15

Oral

Question 16

What are 4 effects of GH when given to adults?

Answer 16

• Improves wellbeing and quality of life
• Decreases abdominal fat
• Improves CV function
• Decreases cholesterol

Question 17

What hormone mainly controls thirst and water regulation?

Answer 17

ADH

Question 18

Where is ADH synthesised and where is it released?

Answer 18

Synthesised- hypothalamus

Released- posterior pituitary

Question 19

Where is the predominant site of the action of ADH?

Answer 19

Kidneys

Question 20

What receptors does ADH stimulate in the kidneys?

Answer 20

V2

Question 21

What does ADH stimulating the V2 receptor do?

Answer 21

Allows the collecting ducts to become permeable to water via the migration of AQP2 channels, thus allowing reabsorption of fluid

Question 22

What is the overall result of ADH secretion?

Answer 22

Decreased diuresis and overall retention of water

Question 23

What other receptors does ADH target at high concentrations?

Answer 23

V1 in vascular tissues

Question 24

What effect does ADH have when it binds with V1 receptors?

Answer 24

Vasoconstriction

Question 25

What are changes in plasma osmolality sensed by?

Answer 25

Osmoreceptors in the anterior hypothalamus

Question 26

At what osmolality is ADH secretion suppressed?

Answer 26

< 280

Question 27

If plasma osmolality increases, what happens to the secretion of ADH?

Answer 27

Increases

Question 28

What is nephrogenic DI?

Answer 28

The renal tubules are resistant to ADH (receptor abnormality)

Question 29

What can cause nephrogenic DI?

Answer 29

Lithium, hypokalaemia, hypercalcaemia, genetics

Question 30

What is cranial DI?

Answer 30

A problem secreting ADH from the posterior pituitary as a result of hypothalamic disease

Question 31

What can cause cranial DI?

Answer 31

Tumours and metastases, granulomatous disease, trauma

Question 32

How do you calculate serum osmolality?

Answer 32

2Na + 2K + glucose + urea

Question 33

What is the normal range for serum osmolality?

Answer 33

285-295

Question 34

What are the main clinical features of DI?

Answer 34

Polyuria and polydipsia

Question 35

What is the most common cause of DI?

Answer 35

Hypothalamic-pituitary surgery

Question 36

What happens when DI occurs following hypothalamic-pituitary surgery?

Answer 36

It is transient and usually remits after a few days-weeks

Question 37

What is familial isolated vasopressin deficiency?

Answer 37

Causes DI from a young age and is dominantly inherited

Question 38

What type of disease is Wolfram Syndrome?

Answer 38

Rare, autosomal recessive

Question 39

What diseases does Wolfram Syndrome comprise?

Answer 39

DI, DM, optic atrophy, deafness

Question 40

Where is the mutation that causes Wolfram Syndrome?

Answer 40

WFS1 gene on chromosome 4

Question 41

What may an MRI show in Wolfram Syndrome?

Answer 41

An absent or poorly developed posterior pituitary

Question 42

What will plasma and urine osmolality be in DI?

Answer 42

Plasma- high | Urine- low

Question 43

What will the sodium concentration be in DI?

Answer 43

High

Question 44

What will happen when there is fluid deprivation in DI?

Answer 44

The urine still will not concentrate

Question 45

What is the main test for DI?

Answer 45

Water deprivation test

Question 46

What would be a normal response following a water deprivation test?

Answer 46

Serum osmolality remains within the normal range | Urine osmolality > 600

Question 47

What would be a DI response following a water deprivation test?

Answer 47

Serum osmolality rises above normal without adequate concentration of urine osmolality (serum > 300, urine < 600)

Question 48

What type of DI is present if desmopressin still will not concentrate the urine?

Answer 48

Nephrogenic

Question 49

What type of DI is present if desmopressin causes the urine osmolality to increase by 50%?

Answer 49

Cranial

Question 50

What treatment options are there for DI?

Answer 50

- Nasal desmospray 10-60mcg/day - Oral desmopressin tablets 100-1000mcg/day - IM desmopressin injection 1-2mcg/day

Question 51

What is syndrome of inappropriate ADH secretion?

Answer 51

Ectopic production of ADH

Question 52

Name some causes of inappropriate ADH secretion?

Answer 52

Carcinoid tumours, pulmonary lesions, CNS damage, alcohol withdrawal, porphyria, drugs

Question 53

What does inappropriate ADH secretion cause?

Answer 53

Retention of water and hyponatraemia

Question 54

What is the presentation of inappropriate ADH secretion?

Answer 54

Usually vague, with confusion, nausea, irritability and later on fits and coma

Question 55

What is the main treatment of inappropriate ADH secretion?

Answer 55

Treat the underlying cause

Question 56

What is the most effective symptom relief for ectopic ADH production if patients can tolerate it?

Answer 56

Fluid restriction to 500-1000ml per day

Question 57

What drug is used for ectopic ADH production if fluid restriction isn't tolerated?

Answer 57

Demeclocycline

Question 58

What drug can be used in the long run of inappropriate ADH secretion?

Answer 58

Vasopressin V2 antagonists